The present invention concerns a machine height measuring method and a machine height measuring device for a surveying machine and, particularly, it relates to a machine height measuring method and a machine height measuring device for a surveying machine which is of a simple constitution and easy to use.
For measuring distance and angle by using a surveying machine, it is necessary to recognize a predetermined point as a reference for the surveying machine (machine height) and, for this purpose, machine height has been measured so far by using a tape measure. However, the measuring method using a tape measure has the disadvantage of poor measuring accuracy. Because of these considerable errors, various kinds of devices have been proposed for measuring machine height.
For instance, according to Japanese Patent Laid-Open Hei 6-194168, a delivery member disposed to a predetermined portion of a surveying machine is drawn out and put on a target, the delivered amount of the delivery member is read by an encoder, and machine height is calculated based on the read value of the encoder reading means.
Furthermore, there is a known technique of detecting machine height by an optical means (refer, for example, to Japanese Patent Laid-Open Hei 4-198809 and Hei 5-248865).
For example, the technique proposed in Japanese Patent Laid-Open Hei 4-198809 concerns a machine height measuring device comprising a telescope supported rotatably around a horizontal center axis for collimating a reference point to be observed, a reflection member disposed at a predetermined distance from the machine center point for reflecting the collimation axis of the telescope, a reflection member disposed at such an angle that the reflected collimator axis crosses a vertical line passing through the machine center point, a detection means for the angle of the telescope relative to the horizontal axis, a detection means for the angle made by the reflected collimation axis relative to the collimation axis, a calculation portion for calculating machine height based on a vertical angle or an angle of elevation of the telescope, an angle made between the collimation axis and the collimation axis reflected by the reflection member and a predetermined distance from the machine center point to the reflection member when the reference point disposed on the vertical line passing through the machine center is collimated by the telescope by way of the reflection member.
Further, the technique proposed by Japanese Patent Laid-Open Hei 5-248865 comprises converting an optical path of a measuring light emitted from an optical wave distance measuring device from a first optical member disposed ahead of an objective length of an optical wave distance measuring device downwardly at a right angle, further reflecting the emitted light from the first optical member by a second optical member and feeding back the same along the optical path to the optical wave distance measuring device thereby conducting optical wave distance measurement, measuring a distance from the machine origin to the second optical member of the optical wave distance measuring device, obtaining a distance corresponding to the machine height of the optical wave distance measuring device based on the distance and determining an accurate machine height according to the distance determined by the optical wave distance measurement and a positional relationship between the first optical member and the second optical member.
Further, as a method of using a vertical scale and a horizontal scale, a technique proposed by Japanese Utility Model Laid-Open Hei 5-6318 has been known. The technique includes a vertical scale erected vertically on a reference line by way of a stand and a horizontal scale contained in the vertical scale drawably from an optical vertical position to a horizontal direction of the vertical scale in which a line of a predetermined size from a reference line is marked to a stepped portion by merely disposing the vertical scale vertically on a reference line such as relief ink.